swapping company isp

Reasteh

Reasteh

Reasteh

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Joined
6 Jul 2007
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431
Location
Notts, UK
How does one go about swapping the isp of a company with the internet going down as it needs to be up 24/7. Do some isp allow you to stay online whilst you migrate or what?

tia
 
It depends on if you are using the same physical cabling. If the new ISP are putting in a new xdsl/leased line or fibre then you can do a paralell install and test without affecting the existing line. You can then have a minimal outage of just a few minutes to reconfigure your network.

If this is a small office with just xdsl and you are migrating to a different ISP then it can be a different story completely. Iy could be down for a few hours while the migration goes ahead.
 
Having done this several times on all different types of WAN links my opinion is it's always best to parallel install. Sometimes it costs a bit extra like having an extra local loop run but if it's mission critical to have net access then there is no other way of guaranteeing constant uptime.
Dependant on your kit you can either load balance the two links so that you can literally have 100% uptime or at worst you have downtime of however long it takes to swap a cable over and enter username, password and DNS servers.
 
yeah, i had to do this at work. Our internet is a business critical service, but at 6.5km from the exchange we only get 512kbps at best. We have 2 adsl lines, one acted as a failover. But the primary got so crap that we now use the 2nd line only.
Bottom line, if its a business critical service for you, then get a 2nd line in and run parallel, until its all sorted. You'll still have some delays at your hosting end when they update 'A' and 'MX' records, usually 48 hours to propogate throughout the DNS servers in the world.
Of course this doesn't disallow you internet connection, it just delays mail between certain servers for a while.
 
k.Jacko said:
yeah, i had to do this at work. Our internet is a business critical service, but at 6.5km from the exchange we only get 512kbps at best. We have 2 adsl lines, one acted as a failover. But the primary got so crap that we now use the 2nd line only.
Bottom line, if its a business critical service for you, then get a 2nd line in and run parallel, until its all sorted. You'll still have some delays at your hosting end when they update 'A' and 'MX' records, usually 48 hours to propogate throughout the DNS servers in the world.
Of course this doesn't disallow you internet connection, it just delays mail between certain servers for a while.
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MX records shouldn't be an issue as you can have more than one. Just add a new one and increase the MX preference value for the old one so it will use the new one once it's propagated automatically. The only one that might be an issue is web hosting but I'd assume for a smallish business you'd host that off site?
 
yeah, we have 2, it depends on how often in day your isp updates their records. Our does every 2 hours, but our old one was just once a day.
 
Tbh I think if you keep both links running for say a week you should be able to migrate everything over seemlessly. Just monitor traffic coming in on the new link to varify what's migrated successfully then when all services have decommision the old link.

If you use NAT as I'm sure you do, your port forwards and 1:1 translations can be set up for both WAN breakouts so that whichever link requests come in on they will always find the server. That way when the DNS records update it should just work straight off. Say UK DNS has replicated but US hasn't, the UK can use the new link and the Us can use the old link and it'll still work. This is easiest with two routers but if you have just a single router + stand alone modems then you can still do it using a separate NAT pool.

I'm just thinking out loud here but I'm sure if you think for more than the 5 mins I have you can achieve 0 downtime here :)
I'm going to stop suggestsing things now else I will be forced to charge you all consultancy fees as it's getting to the point where we're going to get technical :p
 
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ch0ke said:
if its business critical you shouldnt be using adsl at all

leased line.
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Oi! high horse-rider! :p SMB's can still have mission critical services like broadband, but lack the huge budget required for leased line.

i have just finally persuaded the boss to sign up on leased line after many adsl failings, but at over 10x the monthly premium, its not a choice SMB bosses will make lightly no matter how essential you tell them it is.
 
k.Jacko said:
Oi! high horse-rider! :p SMB's can still have mission critical services like broadband, but lack the huge budget required for leased line.

i have just finally persuaded the boss to sign up on leased line after many adsl failings, but at over 10x the monthly premium, its not a choice SMB bosses will make lightly no matter how essential you tell them it is.
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Well to give yourself a bit better redundancy keep the adsl line as a backup. Use something like a Cisco 1841 with adsl wic and have the ISP setup OSPF or another failover routing protocol. Trust me, leased lines can still have issues. If its something like a BT WES10 then you are totally reliant on the fibre into the building. At a prevoius company I worked for, a LES10 fibre was cut in the street and it took 5 days to get backup.
 
pdw8 said:
Well to give yourself a bit better redundancy keep the adsl line as a backup. Use something like a Cisco 1841 with adsl wic and have the ISP setup OSPF or another failover routing protocol. Trust me, leased lines can still have issues. If its something like a BT WES10 then you are totally reliant on the fibre into the building. At a prevoius company I worked for, a LES10 fibre was cut in the street and it took 5 days to get backup.
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Stuff like that is rare and not really worth worrying about. If a 3rd party is involved and damages the cable you can sue them for any damages you incur as a result of their negligence. Stuff like adsl failures are covered by the ISPs SLA and you'll get. One leased line over fiber would be fine, however if you're not a large-ish business big leased lines arn't economically viable.
 
I think thats upto the client really. I have been involved in dozens of similar projects and nearly all the client requested an adsl/sdsl backup to the leased line. They ranged from a 10 user recruitment company to a Housing Association HQ with 40 odd users.
 
k.Jacko said:
Oi! high horse-rider! :p SMB's can still have mission critical services like broadband, but lack the huge budget required for leased line.

i have just finally persuaded the boss to sign up on leased line after many adsl failings, but at over 10x the monthly premium, its not a choice SMB bosses will make lightly no matter how essential you tell them it is.
Click to expand...

Hardly, we have plenty of customers with 20 users or less on non xDSL circuits, usually something in the order of 4 over 10Mbps. If you're internet access is supposedly critical, you're a mug running without a backup, let alone on DSL. DSL is going to have next to no comeback if it's down for a week even, you might get a months rental back but you've basically no hope of compensation for lost business.
 
I have to agree with bigredshark on this one. If you're company is RELIANT on the internet to survive in whatever manner it is mission critical and should have another solution running in place in case there is a failure.

Where I am we have seperate DSL lines and providers in case anything happens. We are not 100% reliant on the internet but it's pretty damn important.

In the event of supreme emergency you always have laptops and wireless data cards, depending on how much usage you are going to put them through they should last for basic tasks in a time of crysis.

With regards to the OP, yes its possible and there has been some good advice already in this thread to consider!
 
The other thing to consider is if the internet needs to be up 24/7 for inbound traffic (like a website), in which case you have a problem as no ISP will let you migrate your IP address (unless you have your own AS etc etc) and you're going to need to change DNS and allow it to propagate.

We did have a customer who ran two ADSL lines from different providers, better than nothing by a long way and I suspect a lot of people do it, but they had the misfortune of a line card failing in the dslam, at which point their multiple providers were no use to anyone.
 
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